Hydraulic sand feeder



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2 Sheets-Sheet 1 l I "l" W. L. KEEF ER HYDRAULIC SAND FEEDER Filed Deo.

April 3, 1945.

rwe/Mm April 3, 1945. w. L. KEEFER 2,372,957 HYDRAULIC SAND FEEDER i Filed Dec. 25, 1943 2 Sheet-Sheet 2 Syvum/vbo@ Patented Apr. 3, 1945 UNITED STATES 'TENT OFFICE HYDRAULIC SAND FEEDER Application December 23, 1943, Serial No. 515,445

(Cl. l-l2) 9 Claims.

The present invention relates to apparatus for storing and feeding an abrasive such as sand in a owable condition to a hydraulic blast gun wherein the sand particles are moved forwardly by means of a high velocity jet of liquid. The invention more specifically pertains to apparatus for supplying wet sand in such a fluid condition that the mixture or slurry may be drawn into the hydraulic blast gun by the injector action developed in the gun.

A hydraulic blasting system includes a gun having a nozzle through which a stream of liquid such as Water is forced at high velocity. This water jet is employed to propel an abrasive medium into engagement with an article or a surface to be blasted. The abrasive is necessarily made wet by the water jet and the expended water and abrasive are collected in a sump for reuse. In view of the fact that the abrasive is wet, and since molding sand is removed from some of the articles cleaned and mixed with the spent abrasive particles, sand is usually employed as the abrasive medium. The wet sand recovered for reuse in the blasting operation presents a problem in the handling thereof in that this sand cannot be readily supplied to the blast gun. The wet sand readily packs and must be maintained in a somewhat fluid state if it is to be drawn into the hydraulic blast gun by an injector action created within the gun.

Accordingly it is an object of the invention to provide means for storing a quantity of Wet sand to provide an adequate supply for a hydroblast gun including means for supplying liquid to the wet sand at various points in the storage means so as to provide a iiowable mixture of sand whereby the sand slurry may be readily conveyed to the blast gun.

Another object of the invention pertains to the provision of means for preventing the abrasive material used by a hydraulic blast'gun from packing within a hopper supplying the gun including means for preventing the abrasive material from obstructing the supply line leading from the hopper to the blast gun.

A more specific object of the invention resides in providing a relatively large hopper for storing a quantity of Wet sand including means associated therewith for supplying liquid at various zones within the wet sand and for supplying liquid adjacent an outlet orifice for the sand to prevent packing of the wet sand and for rendering the abrasive material sufciently uid for moving to a hydraulic blast gun through a supply line.

in the hose in the rst instance and thereby maintaining the supply line open for themovement of the sand therethrough from the supply hopper as a result of a partial vacuum generated by the hydraulic blast gun.

Other objects and features of the invention will be more apparent to those skilled in the art of hydroblasting upon consideration of the accompanying drawings and the following detailed descriptionwherein an exemplary embodiment of the invention is disclosed.

In the drawings:

l is a plan view of the hopper or bin for storing a quantity of abrasive in sucha lowable condition as to be drawn into a hydraulic blast gun,

Fig. 2 is a sectional elevational view of the hopper shown in Fig. 1 and embodying features of the invention.

Fig. 3 is an enlarged sectional view of the lower end portion of the hopper illustrating details thereof.

Fig. l is a side elevational view of the lower end portion of the hopper taken at right angles to Fig. 3.

Referring to the drawings there is shown at l0 a hopper or bin which is adapted to receive and store a quantity of abrasive for use in connection with a hydraulic blasting operation. In carrying out a hydroblasting operation a gun is employed to which liquid under pressure such as Water is supplied to form a high velocity jet. This jet is usually so arranged as to develop a partial vacuum within the gun and thereby draw or suck the abrasive material into the gun. The high velocity jet is also adapted to entrain the abrasive material and propel the abrasive particles forwardly as a forcible blast stream into engagement with the surface or article to be blasted. In carrying out such a, blasting operation the abrasive material becomes wet by the liquid propelling Inedium and it is customary to reuse the abrasive. In blast cleaning castings the molding sand and core sand also become wet and this material becomes intermingled with the blasting abrasive. Thus the abrasive employed in hydroblasting is usually wet sand. The Wet sand vprovides a serious problem in endeavoring to return the wet abrasive particles to the blast gun. This wet abrasive material has a tendency to pack and block apertures and small passages such as employed in the abrasive supply apparatus and in the feed line extending to the hydraulic blast gun. This problem has been encountered in the past in connection with hydroblasting systems and it has often been found that the prior types of sand feeding devices failed to function satisfactorily in that the wet sand packs or settles to such an extent that the gun often functions without any sand being supplied thereto. The present invention thus provides means for preventing the packing of the wet sand stored in the hopper or bin I and adjacent the outlet orice therefor and at the same time rendering the sand sufliciently fluid for facilitating the movement thereof through the abrasive supply line to the gun.

The abrasive may be supplied into the hopper I0 in any suitable manner and in the embodiment illustrated a chute I2 is provided through which the wet sand is admitted to the hopper I0 `from any supply source such as from classifying apparatus which processes the wet sand received from the blasting booth or room. The sand supplied to the hopper I 0 may contain some moisture and as the abrasive lls the hopper I0 the outlet end of the chute I2 is blocked when the sand assumes its normal angle of repose as indicated at I4 in Fig. 2. The sand is preferably delivered to the chute or spout I2 in such quantitles as to maintain the bin I0 substantially full even when the blast gun is functioning.

'Ihe hopper I0 may be supported in any suitable'manner such as by means of standards or legs I5 two of which are shown in Fig. 2. The hopperl or bin I0 is reinforced by an annular ring member I1 which may be welded to the bin. The legs or standards I5 preferably depend from the ring member I1. The hopper I0 may be of any suitable cross sectional shape and in the embodiment illustrated is cylindrical at the upper portion thereof. The lower end of the hopper is provided with inwardly sloping side walls and in the embodiment depicted in the drawings the base portion is frusto conical shaped as shown at I6. A substantially cylindrical shaped tubular member I8 is attached to the inverted apex portion of the conical shaped base I6. The tubular member I8 may be welded to the base portion I6 as indicated at I9 in Fig. 3 to provide a liquid tight connection between these parts. The tubular member I8 terminates at its lower end to provide a relatively large opening through which the sand may move downwardly into a cup member 2I as shown in Fig, 3.

The cup member 2| is preferably mounted in a removable manner so that the lower end of the sand hopper may be opened for the purpose of inspection and for removing any large particles which may inadvertently find their way into the sand hopper and for facilitating the assembly of parts of the apparatus as hereinafter described. Thus the cup member may be pivotally mounted at the lower end of the sand hopper. An exemplary arrangement includes an arm 22 secured to the cup member 2| and pivotally connected to a bracket carried by the tubular member I8. The arm 22 and the bracket 20 may be connected by means of a pin 26 so as to provide a hinged mounting for the cup shaped member 2I. The opposite side 0f the cup member 2I is provided with a suitable locking arrangement so as to maintain the cup member in a position to close the lower end of the tubular member I8. In the embodiment illustrated a swingable bolt 28 is carried by a bracket 29 projecting from the tubular member I 8. The bolt 28 passes through a lug 3| extending laterally from the cup member 2| whereby this closure member may be clamped against the lower end of the tubular member I 8. A gasket such as a yieldable or resilient washer 32 may be interposed between the lower end of the tubular member I8 and the periphery of the cup member 2|. An annular groove is provided in a ange portion of the cup member to facilitate the mounting of the gasket 32.

The inverted apex portion of the cup 2| is provided with an outlet orifice 33 through which the abrasive material is adapted to move and pass into ia tube such asa hose 35 extending to the blast gun. The invention includes means for preventing the blocking of this outlet orifice by packing of the wet sand adjacent the outlet aperture. An embodiment of such means pertains to apparatus for supplying liquid to the abrasive within the hopper I Il and to the sand adjacent the outlet orifice 33. Thus liquid such as water may be supplied to the abrasive within the tubular member I8 and at various points or zones thereabove so as to prevent the packing of the wet sand and to render the abrasive in a owable condition for moving through the outlet orifice 33. Such means may take the form of a pipe 36 arranged within the hopper I6 extending substantially vertically therethrough and maintained in such a position in any suitable manner such as by means of spider arms 38 shown in Fig. 1. The arms 38 may be welded to the tank I0 and to a reinforcing ring member 39 arranged around the upper end portion of the hopper IIJ. The pipe 36 is preferably closed at its upper end to prevent the entrance of foreign material thereto which would eventually obstruct the outlet orifice at the lower end of the sand hopper.

A liquid such as water is supplied to the pipe 36 from any suitable source and preferably in a quantity corresponding substantially to the quantity of sand and water withdrawn from the hopper I0 during the blasting operation. The water may be supplied to the pipe' 36 through a conduit M. A tube 42 extends laterally from the pipe 36 whereby the water supplied by the conduit 4I will also enter the bin above the sand within the hopper Ill. The liquid or water supplied to the conduit 4I preferably is so controlled that the level of the water in the hopper I0 and in the pipe 36 does not rise above the level indicated at M in Fig. 2. The pipe 36 extends downwardly through the central portion of the hopper I 0 and may be supported at its lower end rby spider arms (not shown) similar to the arms 38 employed at the upper end of the bin I0. The pipe 36 terminates near the lower end of the hopper I0 and in substantial axial alignment with the tubular member I8. Thus liquid supplied through the conduit 4I is applied to the abrasive within the hopper I0 through the opening 40 at the lower end of the pipe 36.

The pipe 36 may be provided with a series of openings at spaced intervals along its length whereby the liquid or water therein may be applied to the sand within the tank or hopper III at various zones or points so as to prevent packing of the abrasive within the hopper. The pipe 36 may be provided with a group of openings 46 which may be arranged at circumferential spaced points around the pipe 36 through which the water may pass outwardly into the sand hopper. A shield 4l attached to the pipe 36 in any conventional manner such as by welding is provided .for the tting 66. The opposite side of the :lit-

.f'or preventing the abrasive within the hopper l 0 `from obstructing or blocking the openings 46.

Anotherseries of openings 48 .may be provided in the pipe 36 at a point below the openings 46 The openings 43 are also provided with shielding means for preventing the sand entering the pipe 36 through the openings 48 and thismeans may take the form yof an annular member 49 embracing and secured to the pipe 36. A further series of `openings l may be provided in a still lower part of the pipe 36 and these openings are likewise maintained free o f the presence of sand within the hopper l5 by means of a shield 52. The shields for the openings in the pipe 35 are preferably frusto conical shaped so that the sand when assuming an angle of repose will provide a hollow annular space under each shield. The openings arranged at dilferent positions lengthwise of the pipe 36 thus serve to supply liquid or water to the abrasive within the tank at various zones to prevent packing thereof.

The invention includes further means for applying liquid to the abrasive or sand adjacent the outlet orifice 3h of the hopper and this means may take the form of a jacket 56 surrounding the tubular member i8. The jacket 456 may be secured to the tubularmember i8 in a liquid tight manner such as yby welding. The jacket arrangement thus provides an annular chamber 51 around the tubular mem-ber i8. The liquid or water from the pipe 36 may be supplied to this annular chamber 5i by means of a conduit shown at 58 in Fig. 2. The tubular member I3 is provided with a series of circumerentially spaced openings Si) all communicating with the annular chamber 51 whereby liquid or water from the pipe 3'6 may pass through the conduit arrangement 58 into the annular chamber 51 and through the openings 50 into engagement with the abrasive particles within the tubular member I8 to prevent packing of the abrasive thereinand for rendering the wet sand in such a fluid state as to readily pass through the outlet orifice 33 provided at the lower end of the cup member 2l.

The size of the outlet orifice 33 is of importance i in carrying out the invention and it is for the purpose of adjusting the size of the outlet opening that a removable apertured member or washer 5l is provided in the lower end of the cup member 2l. on an annular shoulder Aformed in the cup member 2| and the size of the opening therein may be altered by replacing the washer f5! with an apertured member having a larger or smaller opening. 'I'he apertured member 5l may be held in an operative position by means of a split ring 62 engaging an annular groove in the cup member 2l as shown in Fig. 3. The apertured member 6I may be mounted on the shoulder adjacent the orifice 33 by swinging the cup member 2l to an open position. In a like manner the washer 6l may be replaced when worn by moving the cup member 2| to the open position.

The slurry of abrasive and liquid passing through the outlet oriiice 33 is adapted to pass into a tting Se provided with transparent side walls or windows El whereby the ow of abrasive into the sand hose 35 may be observed. The fitting B is preferably removably mounted at the lower end of the sand hopper assembly so as to permit cleaning of the fitting. Thus the tting 66 may be hinged to the lower end of the cup member 2| by means of an arm 63 pivotally attached to a bracket S9 carried by the cup member and a pin 'l0 providing a hinged connection The apertured member Si may be seated ting is provided with a lug 7l for clamping the fitting against the lower end of the cup member A gasket 12 may be interposed between the fitting 66 and the cup member 2l as shown in Fig. 3. The iitting 66 is provided with a passage 'J3 preferably sloping towards the sand hose 35 as shown in Fig. 3.

Another feature of the invention pertains to the provision of means for supplying liquid to the fitting 66 so as to add further fluid to the sand and water escaping from hopper .Hl through passage i3. The fitting 66 is provided with a relatively small passage 'l5 of much smaller cross sectional dimensions than the passage 'I3 or .the area of the opening in the washer 6|. Liquid may be sup-plied through the passage 16 under pressure such as water from a municipal water system. The water supplied through the passage 'l is thus under pressure ofapproxim'ately to 100 pounds per square inch and this water may be supplied through a pipe or hose indicated at 'll connected in any conventional manner to the fitting SB adjacent the passage 16. The liquid entering the fitting through the passage 1S renders the abrasive or .sand more iiuid and permits this mixture to bereadily drawn by the suction generated by the blast gun through the hose veloped in the hose by the blast gun draws la greater quantity of material from the hopper Ill because the eiiective area of the orifice 33 has greater dimensions than the passage 76.

The invention includes means for positively interrupting the supply of abrasive from the hopper lll when it is desired to stop the operation of the blast gun. The apparatus thus includes a plug or stopper 8D mounted for closing the opening in the apertured member El. The stopper or plug Sil may be formed of any suitable resilient material is preferably provided with a frusto conical portion 3l adapted to engage a corresponding seating surface on the apertured member 5i. The plug or stopper 8l! is mounted on the lower end 'of an operating rod or bar 82 movable vertically through the pipe 3E as shown particularly in Fig. 2. A guide bearing 83 may be mounted in the tubular member I8 providing a proper guiding support for the lower end of the rod 82. The upper end of the rod 82 extends through a guide opening in the means covering the upper end of the pipe 36. The rod 82 may be actuated by a crank arm 84 pivotally mounted at the top of the sand hopper i8. An operating shaft 8B may be provided for manipulating the crank arm 84 and the shaft 8S is provided for actuation by the operator of the blast gun.

Thus when it is desired to interrupt the operation of the blast gun the operator turns the until all of these abrasive particles are projected from the gun. After the valve is closed the water or liquid entering the tting 86 through the passage 16 will flush any sand particles forwardly to clear the tting and the hose 35 of any abrasive particles which may later cake in these passages particularly when the blasting operation is discontinued for a considerable period. The city Water supplied through the hose 'l1 may be interrupted and thereafter the blast gun may be shut down without danger of the hose or gun being filled with sand so as to block the small passages therein when it is desired to again initiate the blasting operation.

The apparatus may include means for adding a rust inhibiting substance to the hydroblast stream. Thus a tank 90 may be mounted on the standards I5 as shown in Fig. 2. The tank 90 may include rust inhibiting material 9i such as potassium dichromate crystals. The water supplied through th hose 1l' passes through a pipe 92 and a valve 93. When it is desired to include the rust inhibiting substance in the blast stream the valve 93 may be closed and a valve 94 opened whereby the water from the city main passes through the tank S0 into the presence of the rust inhibiting crystals 9| and into the fitting 66. In a like manner the water from the city main may be completely interrupted by closing the valves 93 and 94 or the water from the city main without rust inhibiting material may be supplied by closing the valve 94. A valve (not shown) may be arranged in the pipe 92 to interrupt the supply of auxiliary liquid to the passage 16.

In operation of the apparatus the abrasive material is admitted to the hopper I0 in suicient quantity to substantially fill the bin. The abrasive is usually wet as hereinabove described and these wet particles assume substantially the position illustrated in Fig. 2. A liquid is supplied to the hopper l0 through the conduit 4| and the tube 42 so as to substantially saturate the abrasive material within the bin.

The initiation of the blasting operation will cause a partial vacuum to be generated in the blast gun as a result of the high velocity liquid jet'passing therethrough. The partial vacuum will be developed within the supply line 35 and therefore applied in the passage 13 and in the orice 33. Then the valve 80 may be moved by raising the rod 82 to'open the outlet orice for the hopper I0. The liquid supplied to the pipe 36 will in part escape through the openings 46 and the openings 48 and the openings 5| to various zones within the hopper l0. This liquid abrasive material to pass to the blast gun. The liquid under pressure moving through passage 16 also tends to prevent the formation of any blocked condition within the sand hose 35 and within the fitting 66.

The valve 80 is moved to a closed position -when it is desired to stop the blasting operation. The blast gun is preferably operated for a short period after the valve B is closed so as to draw the residual abrasive particles fromthe passage 13 and the fitting 66 and the sandhose 35. The liquid supplied through the passage 16 may be continued during this period to further assist in removing residue particles from the supply line and for clearing the blast gun of abrasive particles. Thereafter the liquid under high pressure providing the high velocity blast jet in the gun may be stopped after which the valves 93 and 94 may be closed to interrupt the supply of liquid through the passage 16.

While the invention has been described with reference to specific structural details it will be appreciated that changes may be made in the apparatus. Such changes may pertain to the shape of the hopper I0 and variations in details of mounting the various parts may be made without departing from the spirit and scope of the invention as set forth in the appended claims.

I claim:

l. In apparatus for feeding abrasive particles to a hydraulic blast gun, a hopper for storing wet abrasive particles, inwardly converging walls at the lower end of said hopper, means closing the lower end of the hopper and having a discharge orifice therein, means providing an annular chamber around the hopper adjacent said converging walls, means supplying liquid into said annular chamber, and said hopper having circumferentially spaced openings therein com- 1 40 municating with said annular chamber whereby will prevent packing of the abrasive vertically above the outlet orifice 33. The liquid may also pass from the pipe 36 through the pipe arrangement 58 into the annular chamber 51 and through the openings 60 into engagement with the abrasive particles in the lower end portion of the hopper and within the tubular member I8. 'I'his liquid and that supplied through the opening 40 renders the abrasive in the lower portion of the hopper sufciently fluid for flowing through outlet orifice 33 to be drawn through the hose 35 to the blast gun.

The liquid supplied by the hose 'H may be admitted to the fitting 66 when the blast operation is initiated to further maintain the abrasive in a flowable condition as it passes through the tting 66 and the hose 35. The liquid supplied through the passage 16 is in such small metered quantities as compared to the volume of abrasive material entering the fitting through the passage 13 as to permit an adequate supply of liquid is supplied to the abrasive adjacent the.

discharge orifice.

2. In apparatus for feeding abrasive particles to a hydroblast gun, a hopper for storing wet abrasive particles, said hopper having a discharge orifice in a lower portion thereof, a pipe embedded in the abrasive particles above said discharge orifice, means for supplying liquid into said pipe, said pipe having an opening therein .through which the liquid may escape into the hopper, and means extending outwardly from said pipe terminating in an edge so spaced from the pipe thatthe abrasive issuing at its angle of repose below said edge engages the pipe below said opening.

3. In apparatus for feeding abrasive particles to a hydraulic blast gun, a hopper for storing wet abrasive particles, said hopper having a discharge orice in a lower portion thereof, a pipe extending vertically of the hopper through the abrasive particles above said discharge orifice, means for supplying liquid into said pipe, said pipe having openings therein through which said liquid may escape into the presence of the abrasive within the hopper, and an annular shield carried by the pipe preventing the abrasive particles from obstructing said openings.

4. In apparatus for supplying abrasive to a hydroblast gun, a hopper for receiving wet abrasive particles, said hopper having an outlet orifice in a lower portion thereof, means for supplying liquid under substantially no'pressure to a plurality of points adjacent said outletorifice to prevent packing of the abrasive particles within the hopper and to render the abrasive fluid for movement through said outlet orice, a tting receiving the abrasive particles passing through said outlet oriice, a suction line drawing the abrasive from said fitting to a blast gun, and means for supplying liquid under pressure to the tting for maintaining the abrasive therein in a owable condition and for assisting movement of the abrasive to the blast gun.

5. In apparatus for feeding abrasive particles to a hydraulic blast gun, a hopper for storing a quantity of wet abrasive particles, removable means closing the lower end of the hopper and having a discharge orifice therein, means supplying liquid into said hopper adjacent said discharge orice, and a removable apertured member within said closure means dening the eiective opening of the discharge orifice.

6. In apparatus for feeding abrasive particles to a blast gun, a hopper for storing abrasive particles, a hinged cup member closing the lower portion of the hopper and having a discharge orifice therein, a shoulder on the cup member .around said discharge orifice, a washer resting v said discharge orice, and means within said pipe for actuating said valve to close and open the discharge orifice.

8. In .apparatus for feeding abrasive particles to a hydraulic blast gun, a hopper for storing4 a quantity of wet abrasive particles, said hopper having a discharge orice in a lower portion thereof, a fitting having a passage therein registering with said discharge orice, means for guiding the abrasive from said tting to the blast gun, means supplying liquid into the hopper adjacent said discharge orice whereby the abrasive particles now from the hopper through the discharge orice into said tting for movement to the gun, and transparent side walls for said fitting whereby the movement of abrasive through the fitting may be observed.

9. In apparatus for feeding abrasive particles to a hydraulic blast gun, a hopper for receivingia quantity of wet abrasive particles, said hopper having an outlet orice in the lower portion thereof, a pipe within the hopper embedded in the abrasive particles and terminating adjacent said outlet orifice, said pipe having openings therein at spaced intervals along the pipe, means providing an annular chamber around the hopper adjacent the outlet orifice, said hopper having openings therein providing communication between the interior of the hopper and the annular chamber, a

. conduit connecting said annular chamber to said 

